In Defence of Liberty

Driven by data; ridden with liberty.

The Gap between Truth and Falsehood

With grim predictability, British newspapers responded to the Office for National Statistics on discrepancies between long-term international migration and National Insurance number registrations with hysteria [1].

This maelstrom of over-reaction and misunderstanding reached its maximal ferocity in The Telegraph, declaring that 2.4m was [2]:

The real number of EU migrants we now know came to Britain.

Their headline accompanied this stark image was for a commentary by Allison Pearson:

The gap between the official migrant figure and the truth is as wide as the Grand Canyon. We are owed an apology.

The carousel of errors


Indeed, we are. (Source: BBC/Telegraph)

The article begins with a series of people who are supposedly owed an apology, and then Ms Pearson writes:

The apologies are due because of report – or, as some will call it, a confession – issued by the Office of National Statistics. And what the ONS admitted to was The Gap.

Official figures show that, the five years to 2015, just under one million immigrants came to this country from the EU, as they are perfectly entitled to do. But hark. Over the same period, the number of National Insurance numbers issued to EU migrants was more than 2.2 million.

In all, the ONS now estimates a total of 2.4 million entered the country. In one year, mid-2014 to mid-2015, a quarter of a million Europeans came in according to the official, yet almost 700,000 bagged themselves a NI number.

Firstly, it is the Office for National Statistics. Secondly, it was a note, not a regular report. Thirdly, the ONS has not changed its estimate for long-term migration from the European Union.

Fourthly, the figure — “a total of 2.4 million” — was achieved by summing the years of long-term visitors and short-term international migration (STIM) visit data, for work, business, or study. In the final year of the STIM data, the higher intentions-based ratio estimate of 800,000 was used [3].

This is erroneous: the short-term migration figures are visits, and not people. The same person could be make two short-term (one to 12 months) visits in the same year, or be both a short-term and a long-term migrant (coming once, leaving quickly, and then arriving again). The sum of these figures was not intended as a simple measure of all immigration into the UK, but to illustrate the flows of people that might require a National Insurance number. The number of people making multiple journeys is expected to be small relative to the total flow, so it may not overly affect the general trends.

Fifthly, the supposed figure of “the official number of EU migrants who came to Britain between 2011 & 2015” is actually incorrect. Summing the five years of long-term migrants from the EU yields 1.004m, not 0.9m.

“Six Newcastles” of people not living in Newcastle

Ms Pearson continues her screed:

Suspicions that the figures were being grossly underestimated, perhaps to spare government blushes, are now confirmed. The extra number of EU migrants the ONS has found down the back of the sofa amounts to six Newcastles.

It’s a stupefying figure, which helps to explain the growing crisis in the NHS, with one migrant registering per minute with a GP in England and Wales.

The ONS note is not nearly as stupefying as Ms Pearson’s article. If she has evidence that the immigration figures are being purposefully and “grossly underestimated”, then Ms Pearson should present it, rather than those vague “suspicions”.

It does not “explain the growing crisis in the NHS”, because these are estimates of short-term visits, by people who have — by definition — already left.

The ONS has not found the “extra number” of migrants “down the back of the sofa”: the ONS regularly report on short-term immigration figures, and have been releasing estimates since 2007. The note was about explaining the difference between long-term immigration statistics and the National Insurance number registrations.

NINo Registrations for the UK, LTIM estimates of immigration to the UK, and STIM estimates of immigration to England and Wales for employment, study or work (other), EU citizens, mid-2003 to mid-2015


Source: Long-term International Migration (LTIM) – Office for National Statistics, Short-term International Migration (STIM) – Office for National Statisics, National Insurance Numbers Registered to Adult Overseas Nationals – Department for Work and Pensions. [Details and Assumptions: ONS]

Ms Pearson persists:

So, how to explain the convenient discrepancy between the number of EU migrants the British people were told were here and the actual figure? Ah, says the ONS, with a lofty air: short-term immigrants have not been included in the tally. They aren’t here for long enough to make a difference, so count them out.

The reason that the ONS does report regularly on short-term immigration is provided in one of the reports itself [4]:

Local authorities are among the major users of short-term immigration statistics. They use estimates for planning and monitoring service delivery, resource allocation and managing budgets.

“The ONS sweetly assumes”

Next, Ms Pearson supposes that the ONS has not considered the possibility of people changing their mind after the International Passenger Survey:

Now, Piotr may, as the ONS sweetly assumes, have had no intention of staying on. But what if he does? Maybe he proves such a dab hand with the plunger that the urge to leave starts to fade. And what if his family joins them? Then we will have lots of little Piotrs in need of schooling and healthcare. (Just think that we need an extra 900,000 school places by 2024.)

Piotr has already left. The ONS estimates of short-term international migration have a time delay, precisely because they analyse switching and the survey is conducted on people leaving the country.

Ms Pearson says the figures “are a million men down”:

Boris Johnson has accused the Government of “terrible dishonesty” and urged it to “man up” about the facts. And, damn it, he’s right.

When your figures are a million men down, and more, it’s time to man up in a serious way.

The immigration statistics are not “a million men down, and more”: long-term migration is defined as more than 12 months, in accordance with the UN definition. The ONS estimate has not changed, and it is disturbing to see such flagrant misunderstanding of statistics forged for political ends.


It is two figures overlaid on the Grand Canyon: both are wrong. (Source: Telegraph)

We look primarily at long-term migration to Britain for its effect on public services and work and taxation since these people are intend to be here for a long time, whereas — by definition — short-term migrants exit in less than a year. This does not mean that this category of migration somehow passes invisibly through our borders.

Ms Pearson is right: we deserve an apology, from the author and her paper.

It should be an apology for this agitpop posing as serious analysis.


[1] Masters, A., 2016. ONS note on Immigration Data Discrepancies. In Defence of Liberty. Available from: [Accessed: 18th May 2016]

[2] Pearson, A., 2016. The gap between ONS migrant figures and the truth is as wide as the Grand Canyon. We are owed an apology. Telegraph. Available from: [Accessed: 14th May 2016]

[3] ONS, 2016. Note on the difference between National Insurance number registrations and the estimate of long-term international migration. Available from: [Accessed: 14th May 2016]

[4] ONS, 2015. Short Term International Migration Annual Report Year Ending: Mid 2013 Estimate. Available from: [Accessed: 14th May 2016]


One comment on “The Gap between Truth and Falsehood

  1. Pingback: The Idiot’s Canyon | In Defence of Liberty

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This entry was posted on May 20, 2016 by in National Politics and tagged , , , .
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